Is sitting the optimal position for measuring Blood Pressure (BP)?

From the Guidelines

Sitting is the recommended position for taking blood pressure measurements, as it provides the most consistent and accurate readings that reflect typical blood pressure. When having your blood pressure checked, you should be seated in a chair with your back supported, feet flat on the floor, and arm supported at heart level, as outlined in the 2021 guideline-driven management of hypertension: an evidence-based update 1. Before the measurement, you should rest quietly in this position for at least 5 minutes, avoiding talking, crossing your legs, or having a full bladder during the measurement.

This sitting position is preferred because it helps to minimize variations in blood pressure readings, which can be influenced by factors such as blood pooling in the legs when standing or uneven blood distribution when lying down. For the most reliable monitoring, take readings at the same time each day, using the same arm and position. If you're checking your blood pressure at home, take 2-3 readings about one minute apart and record the average, as recommended by the 2019 AHA/ACC clinical performance and quality measures for adults with high blood pressure 1.

Some key points to consider when taking blood pressure measurements include:

• Using a validated electronic upper-arm cuff device, as listed on www.stridebp.org, or a calibrated auscultatory device with a low deflation rate, as recommended by the 2020 International Society of Hypertension global hypertension practice guidelines 1
• Ensuring the cuff is appropriately sized for the individual's arm circumference, with the inflatable bladder covering 75%-100% of the arm circumference for manual auscultatory devices, as outlined in the 2020 International Society of Hypertension global hypertension practice guidelines 1
• Taking multiple readings, with at least 2 readings 1 minute apart in the morning and evening, and calculating the average of the last 2 measurements, as recommended by the 2019 AHA/ACC clinical performance and quality measures for adults with high blood pressure 1
• Recording all readings accurately, using monitors with built-in memory and bringing them to all clinic appointments, as recommended by the 2021 guideline-driven management of hypertension: an evidence-based update 1.

By following these guidelines and taking blood pressure measurements in a seated position, you can help ensure that your healthcare provider gets an accurate picture of your cardiovascular health to guide treatment decisions, as emphasized by the 2019 KDOQI US commentary on the 2017 ACC/AHA hypertension guideline 1 and the 2021 standards of medical care in diabetes 1.

From the Research

Blood Pressure Measurement Positions

• The position of the patient during blood pressure measurement can affect the readings, with some studies suggesting that sitting and supine positions may not be interchangeable 2.
• A study found that diastolic blood pressure and heart rate were significantly higher when measured with patients sitting rather than supine, with this effect decreasing with age 2.
• However, another study found that the maintenance of blood pressure upon assuming an upright posture depends on rapid cardiovascular adaptations, and failure of these mechanisms can result in orthostatic hypotension 3.

Orthostatic Hypotension

• Orthostatic hypotension is defined as a decrease in blood pressure of 20 mm Hg or more systolic or 10 mm Hg or more diastolic within three minutes of standing from the supine position 3, 4.
• The detection of orthostatic hypotension requires blood pressure measurements in the supine and standing positions, with a more practical approach in clinics being measurement of seated and standing blood pressure 3.
• Orthostatic hypotension is associated with a significant increase in cardiovascular risk and falls, and up to a 50% increase in relative risk of all-cause mortality 4.

Measurement Considerations

• When measuring blood pressure, it is essential to consider the patient's position, as well as other factors such as age, body mass index, and medication 2, 5.
• The use of a Hawksley random-zero sphygmomanometer or a semi-automatic oscillometric device can provide accurate blood pressure readings in different positions 2.
• The sequence of the positions (sitting or supine) can be randomized to minimize any systematic differences in blood pressure readings 2.